Article 166 of the Constitution of the Republic of Bulgaria states that
the flag of the Republic of Bulgaria is a tricolor: white, green, and red
from the top, placed horizontally. According to the Bulgarian State Seal and
National Flag Act, the three color fields shall be identical in form and
size: Form - rectangular with a 3:5 width-to-length ratio. Size: 18 cm x
30 cm, 24 cm x 40 cm, 90 cm x 150 cm, 129 cm x 215 cm. Colors:
white - with a degree of whiteness not less than 80%, green - #17-5936 TS
according to the Pantone-textile scale, and red - #18-1664 TS according to
the Pantone-textile scale. Standard samples of the colors of the national
flag shall be kept by the Committee of Standards and Metrology.

The protocol manual for the London 2012 Olympics (Flags
and Anthems Manual London 2012) provides recommendations for national flag
designs. Each NOC was sent an image of the flag, including the PMS shades, for
their approval by LOCOG. Once this was obtained, LOCOG produced a 60 x 90 cm
version of the flag for further approval. So, while these specs may not be the
official, government, version of each flag, they are certainly what the NOC
believed the flag to be. For Bulgaria: PMS 3405 green and 485 red. The
vertical version is simply the flag turned through 90 degrees anti-clockwiseIan Sumner, 10 October 2012

"On the eve of 1 November, the Day of the national enlighteners, president
Georgi Parvanov bestowed on every Bulgarian town-hall the national flag,
accompanied by a personal message from him, informed the president's press
service. In his message Georgi Parvanov calls for the Bulgarian flag to be waved
in every municipality with purity and immaculateness as a symbol of the
statehood and the dignity of the Bulgarian people. “On 1 November we pay respect
to all Bulgarian patriots, who devoted themselves to revival and development of
our country. This is a celebration of Bulgarian national spirit and
self-confidence”, reminds in his message the president.

The municipalities that receive the flag these days are 3 742. This is a
third successive initiative of Georgi Parvanov in the framework of the initiated
by him campaign for raising the national flag at important public buildings.
Under the patronage of the president, on 1 November 2004 the national flag was
raised in every Bulgarian school. The next year started the annual ritual of
raising the flag in front of the parade entrance of the president's
institution."

The text of the law on the national coat of arms is published at
www.government.bg, as published in the State Gazette #67 on 05 August 1997:

Article 1.
The coat-of-arms of the Republic of Bulgaria is a state symbol of the
independence and sovereignty of the Bulgarian people and the state.

Article 2.
(1) The coat of arms of the Republic of Bulgaria is a golden crowned lion,
standing on his hind legs, in front of a dark red shield. The shield has a
crown, whose prototypes are the crowns of Bulgarian rulers from the Second
Bulgarian State, with five crosses and another cross above the crown. Two golden
crowned lions, standing on their hind leg, facing the shield, hold it. They
stand on two crossed oak branches with acorns. Under the shield there is a white
band with the flag that reads: “Union Makes Strength”.
(2) The graphical and colour image of the coat-of-arms, established by the
appendix, are part of this law.

Article 3.
(1) The coat-of-arms of the Republic of Bulgaria is on the state seal, as
established by the State Seal Law.
(2) The coat-of-arms of the Republic of Bulgaria, placed elsewhere as well as
the reproduction of the elements of the coat-of-arms on badges, commemoration
medals and others is allowed only under an ordinance of the Council of
Ministers.Ivan Sache, 01 February 2006

The first Bulgarian Constitution (adopted on 16 April, 1879) says in its
23rd article: "The Bulgarian national flag is of three colors, and contain
<consists?> of horizontally placed white, green and red colors".
The second Bulgarian Constitution (adopted on 6 December, 1947) says
in its 97th article: "The flag of the People's Republic of Bulgaria is of
three colors - white, green, red, placed horizontally. In the left upper
corner over the white strip is placed the coat of arms of the People's Republic.
The third Bulgarian Constitution (valid since 18 May, 1971) states in
its 141st article: "The flag of the People's Republic of Bulgaria contains
three colors, placed horizontally in the following order from up to down:
white, green and red. In the left upper corner over the white strip is placed
the coat of arms of the People's Republic."
This text was changed on 27
November, 1990, the new text ("The flag of the Republic of Bulgaria contains three colors, placed horizontally in the following order from up to down:
white, green and red.") was valid until the adoption of the fourth, actual
Bulgarian Constitution (since July 13, 1991).
Ivan Marinov, 20 March 2001

According to Fischer Weltalmanach '99, Russia, at the beginning of the 19th
Century the only independent Slavic state, was the example for all Slavic
states under Ottoman Turk and Austrian-Hungarian rule. These would be would
be Serbia, Slovenia,
Slovakia, Czech Republic, and Bulgaria. In the Bulgarian flag, the blue
stripe was replaced by the freedom color
of green.
Stefan Härtel, 17 October 1999

The flags in green, white and red colours were used by Bulgarian Legia
(revolutionary organisation founded in Serbia by Bulgarian emigrants led
by G. Rakovsky) in 1861-1862. The first white-green-red striped flag was made by S. Paraskevov and presented
to Russian-Bulgarian troops (during the war against Turkey) in the Romanian
town of Braila in 1877. It was a swallow-tailed banner. There was a lion
and inscription "BULGARIA" in the centre (in Cyrillic characters). Now, the
"banner of Braila" is kept in the War Museum in Sofia. The Bulgarian Constitution of 1878 confirmed this flag (but rectangular
and without a lion).
Victor Lomantsov, 03 September 2000

Each year since the fall of the communist government, a ceremony is conducted
in Sofia, where the bishop sprinkles holy water on a symbolic horse's tail
and a flag from the Russo-Turkish war. The flag and horse's tail are provided
by the Museum of Military History. The celebration occurs on January 6,
a religious festival day in Bulgaria. In addition, the bishop throws a
silver cross into a river or lake, from which it is retrieved by a devout
believer.
From news sources provided by David Fowler, 10 January 2000

As far as I am aware, there is no "state flag" prescribed nor used (i.e.,
the national tricolour with the coat of arms in the upper stripe). The
closest thing to it is the Prime Minister's flag,
but with the white stripe double the width. It may be that the former custom of
having the coat of arms in the canton induced some to produce and use such a
flag by ignorance or eagerness, but I would be surprised if such flags would indeed be
used on the state institutions. If it exists, it would look like
this (drawn by Mihail Shcherbak).Željko Heimer, 21 April 2005

Yesterday, there was a memorial service for the victims of the recent terror
attack in Bulgaria. Some candles had small Israeli flags around their holders,
but at least one had small Bulgarian flags. There is clearly a symbol on the
upper stripe (see image), at the hoist, but the picture to too small to make out what it
might be.Nachum Lamm, 29 August 2012

There is an unofficial version of the Bulgarian flag that is extremely
popular, but has zero official status -
http://dariknews.bg/uploads/news_images/201306/photo_verybig_1107050.jpg. It
features the full coat of arms on the left of the flag, but across the white and
green fields only. I think it became popular because people were used to having
the arms at the top-left during communist times, and so they started making this
flag, but with a larger arms because it is more colourful.Nikolai Tihov,
27 June 2013